Watch crystal assembly tool



Jan. 4, 1944. MAlRE I WATCH CRYSTAL ASSEMBLY TOOL Filed March 24, 1942 Patented Jan. 4, 1944 UNITED srATEs PATENT OFFICE Application March 24, 1942 Serial No. 436,016

, In Switzerland May 26, 1941 1 Claim; (Cl. 279-43) This invention relates to tight watch cases and more particularly to watch cases of the type which comprises a round shaped crystal made of a non-breakable material such as, for example, polyvinylic or polyacrylic resins, tightly fitted into the aperture of a crystal holder, for instance of a bezel, a case band, a combined bezel-back and case band, to an improved method of their manufacture and to a tool for working this method.

The invention has for its primary object the provision of means whereby a round shaped crystal made of non-breakable material is readily and easily snapped into its holder without making use of securing or sealing means such as, for instance screws, springs, resilient packings, mastics etc., thus making possible removing and replacing of the crystal even after the watch has gone into the hands of the user without damaging its tightness.

According to the invention the crystal is first deformed by compressing it circumferentially into a slotted sleeve provided with a chucking device and then so reduced in diameter it is introduced still under circumferential tension into the aperture of its holder, where it tends to recover its normal diameter which is somewhat larger than the diameter of the holder's aperture.

A further object of the invention is to provide a waterproof watch case construction which permits of using a case body so called cassolette which is formed of a combined bezel-back and case band made of one piece, thus eliminating the usual screw threads or hinges for securing the back to the case band.

A still further object of the invention is to provide a ready and simple tool for inserting a non-breakable round shaped watch crystal into the aperture of a rigid bezel or other glass holder without deforming it by heating and/or springing it into arcuate form by axially applied pressure.

Other and further objects and advantages of the invention will be hereinafter set forth and the novel features thereof defined by the appended claim.

In the drawing:

Fig. 1 is a plan view of a prefered form of the tool for working the improved method of the invention;

Fig. 2 is a view: partly in elevation, partly in section of this tool;

Fig. 3 is a plan view showing a watch case made in accordance with the method of the invention;

Fig. 4 is a cross sectional view of this watch case and Fig. 5 illustrates a step of the procedure jaccording to the invention.

The tool represented in the Figs. 1 and 2 comprises a slightly conical sleeve l WhiCh'iS formed with six slots 2 extending from its lower end parallel to its sides; the lower end 3 of the sleeve is shown having a cylindrical inner portion 4 of enlarged diameter. 5 denotes a chucking ring provided with two flanges 6, which is mounted on the outer surface of the sleeve so as to be allowed to slide along the same, a split ring I made of a soft metal being located intermediate between the sleeve and the chucking ring. Both the flanges 6 are traversed by a clamping screw 8 provided at one end with a square-head 8', and at the opposite end with a thread 8" engaging the corresponding screW-taped flange 6.

The watch case shown in Figs. 3 and 4 is a socalled cassolette one, it is a Watch case formed of a body 9 which reunites into one piece the back, the caseband and the bezel, and of a round shaped crystal ll made of non-breakable material. lfl denotes a movement ring, the upper end of which is formed with a shoulder l2 adapted to rest on an annular inner shoulder ll of the body 9. The watch crystal II has its downwardly bent rim l5 engaged into the aperture 9a of the case body 9 and snapped into a groove l4 formed on the wall of this aperture adjacent to the edge thereof. The dial [6 becomes to lie flush with the bottom of the groove l4 and a thin ring of metal I! overlaps both this bottom and this dial, the rim l5 of the crystal being adapted to bear upon this ring I'l so as to maintain in place the movement ring In and the watch-movement I8 itself which is commonly secured to the ring II).

In carrying out the method according to the invention (as illustrated in Fig. 5) the clamping screw 8 is first slacked and the chucking ring 5 is raised up to the upper end I of the slotted sleeve I. The crystal II is then seated into the groove 4 (Fig. 2) arranged inwardly on the lower end I" of the sleeve, this groove being so dimensioned as the rim I5 of the crystal projects out from the sleeve. The chucking ring 5 is then lowered along the sleeve and the screw I is screwed on so as to exercise a heavy circumferem tial pressure upon the lower end I" of the sleeve, whereby this end becomes substantially reduced in diameter and consequently the therein seated crystal H is submitted to a heavy circumferential pressure and becomes substantially reduced in ing ring 5 raised, whereby the crystal, after the pressure of the sleeve has been released, immediately tends to recover its normal size. If this size is slightl larger than the aperture 9a, the

crystal will exercise round on the wall of-the aperture a permanent pressure that is sufficient to hold it firmly in place and to secure a, close and tight contact between the crystal and the case body. The sleeve may be removed after the crystal has been released.

Inversely, the crystal may be easily removed from the case body. For 1 this operation the chucking sleeve is placed with its lower end surrouning loosely the projecting portion of the crystal and then tightly clamped by means of the chucking ring 5 and the screw 8, whereby the crystal will be reduced in diameter and easily removed.

It is evident that many changes may be made in the specific construction and procedure described without departing from the spirit thereof as defined by the appended claim.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

A tool for inserting a preformed crystal into the round aperture of a holder comprising a conical longitudinally slotted sleeve, the extreme outerfiend'of thexslotted-slevebeing provided on its inner surface with a groove adapted to seat abortion of the curved rim of a preformed watch crystal so that the extreme outer portion of the rim thereof projects out from said sleeve when clamped thereby, a chucking ring slidably mounted on said sleeve said chucking ring being pro.- v'ided with two flanges, a clamping screw adapted to engage both said flanges and to clamp said ring, and a split ring made of soft metal arranged between said sleeve and said chucking ring so as to facilitate the sliding of said chucking ringalo'ng said sleeve. 7 GEORGES MAIRE. 

